Molecular characterization of a novel NK cell signal transduction molecule: NKR-P1

Abstract

Natural killer (NK) cells are a subpopulation of mononuclear leukocytes that are responsible for the resistance to growth and metastatic spread of a wide variety of tumors. 1 , 3 These cells also seem to be responsible for natural immunity against some viral and bacterial infections. 4 , 6 Virtually all of the NK activity is contained within the population of large granular lymphocytes (LGLs), lymphoid cells characterized by densely staining azurophilic granules. 7-9 In vitro, NK cells have been characterized as nonadherent, nonphagocytic cells capable of mediating, in short-term cytotoxic assays, major histocompatibility complex (MHC)-unrestricted cytolytic activity against virally infected or neoplastic target cells without apparent prior sensitization. 1 , 2.